1. Field of the Invention
The present invention relates to a roll mount connected to a point where vibration occurs such as a connecting point between a vehicle body and an engine or a connecting point between a sub-frame and a transmission, and mounted to attenuate vibration and support a load, and more particularly, to a roll mount having a pocket with an encapsulated magnetorheological fluid (MRF) and coupled to rubber, to actively adjust the damping performance and load supporting force based on application of an electric current.
2. Description of the Related Art
Generally, an engine for a vehicle is coupled to a transmission and mounted in an engine room. In particular, the engine is mounted by being coupled to an engine mount and a transmission mount to support the loads of the engine and the transmission and to attenuate vibration being transmitted to a vehicle body.
The engine or the transmission is positioned on the engine mount or the transmission mount, or the engine mount or the transmission mount is connected to one side of the engine or the transmission. Further, one or more roll mounts are additionally mounted to share and support a variation in load of the engine and the transmission that is generated by inertia of the vehicle. In other words, the engine mount and the transmission mount support loads of the engine and the transmission at both sides of the engine and the transmission, respectively. The roll mounts, are attached and installed to lower sides of the engine and/or the transmission, and are additionally connected to the engine or the transmission, to displacement control and vibration damping.
As shown in the related art with reference to FIG. 1 a structure of the roll mount includes, exterior pipes 11 coupled to both ends of a main body 10 of the roll mount which has a straight or bent bar shape, respectively. Further, rubbers 12 having elasticity and cores 13 positioned at a center of the rubbers 12 are coupled in the exterior pipes 11. The core 13 has a hollow pipe shape to be coupled to a vehicle body member, a sub-frame, the engine, the transmission, and the like by bolting, fastening or the like. The rubber 12 is elastically deformed by loads and vibration input through the core 13.
Additionally, the front exterior pipe and the rear exterior pipe may be formed with a variety of sizes to provide alternate size configurations of the rubber 12 based on the load at the connecting point and the inputted vibration. Further, a larger rubber is fastened to an exterior pipe having an increased diameter, that improves the load supporting force and vibration damping performance. Furthermore, to improve the vibration damping performance (e.g., to induce a greater degree of elastic deformation), the rubber 12 is partially removed (e.g., cut out) to additionally form slits 14 e.g., the slits penetrate upper and lower surfaces of the rubber 12).
Typically, in the roll mount configured as described above, the front core, coupled to the relatively larger rubber, is mounted (e.g., coupled) to a lower portion of the transmission or the engine where vibration occurs. The rear core is coupled to a relatively smaller rubber and is mounted (e.g., coupled) to the vehicle body or the sub-frame. Therefore, the roll mount supports the loads of the engine and the transmission and attenuates vibration. In particular, as a result, the roll mount significantly affects the noise, vibration, and harshness (NVH) performance, handling performance, and the like of the vehicle. In other words, the roll mount is a component that impacts the rolling behavior control for the engine. Accordingly, the noise and vibration felt by passengers may be reduced and the improved performance of the roll mount may improve driving performance of the vehicle.
To improve driving performance of the vehicle (e.g., to more secure support the load of the engine or the transmission) the rubber 12 needs to be manufactured using a material having a relatively low elastic coefficient. However, there is a problem in that vibration is transmitted to the interior of the vehicle when the engine idles. Conversely, when the rubber 12 is manufactured using a material having a high elastic coefficient, the vibration damping performance is improved, but the load supporting performance deteriorates. Therefore, there is a need for a roll mount which is capable of maintaining low characteristics (e.g., a state in which elastic deformation may be more easily carried out) when the engine idles, and adjusts characteristics in response to a driving state when the vehicle starts to move or travels.